As smart devices are applied widely, requirements for data services grow exponentially. To meet people's requirements for Internet access anytime and anywhere, performance of a network system should be improved.
In some communications systems, a signal field (signal field) in a physical layer of a data packet provides a partial association identifier field (field) for carrying a partial association identifier (partial AID, partial Association Identifier) of a target receiving device of the data packet, so that a receiving device may determine, in the physical layer, the target receiving device of the data packet by using the partial association identifier. Therefore, for example, if the receiving device is not the target receiving device of the data packet, the receiving device does not need to continue to parse the data packet. Therefore, communications efficiency is improved, and device burden is reduced. However, due to a limit of a quantity of bits of the partial association identifier (or a quantity of available bits of the signal field), the partial association identifier can distinguish only more than 500 receiving devices, and cannot meet a development requirement as a quantity of users increases quickly. In addition, in some scenarios such as device to device (D2D, Device to Device) communications, a partial association ID field may be set to all zeros, and cannot function normally.
Furthermore, in a system that does not provide a partial association identifier field, for a received data packet, a receiving device cannot identify, in the physical layer, a target receiving device of the data packet, and can only parse a Media Access Control (MAC, Media Access Control) layer of the data packet to acquire a MAC address carried in a MAC frame header, and identify the target receiving device according to the MAC address. That is, after the receiving device receives the data packet, even if the receiving device is not the target receiving device of the data packet, the receiving device should parse the MAC layer of the data packet, because the target receiving device of the data packet can be identified only after the MAC layer is parsed. Therefore, for a device that is not the target receiving device of the data packet, device burden is increased, hardware resources are wasted, and user experience is affected.